다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

Bose-Einstein condensation in a gas of sodium atoms

Topological photonics is a rapidly emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light. Drawing inspiration from the discovery of the quantum Hall effects and topological insulators in condensed matter, recent advances have shown how to engineer analogous effects also for photons, leading to remarkable phenomena such as the robust unidirectional propagation of light, which hold great promise for applications. Thanks to the flexibility and diversity of photonics systems, this field is also opening up new opportunities to realize exotic topological models and to probe and exploit topological effects in new ways. This article reviews experimental and theoretical developments in topological photonics across a wide range of experimental platforms, including photonic crystals, waveguides, metamaterials, cavities, optomechanics, silicon photonics, and circuit QED. A discussion of how changing the dimensionality and symmetries of photonics systems has allowed for the realization of different topological phases is offered, and progress in understanding the interplay of topology with non-Hermitian effects, such as dissipation, is reviewed. As an exciting perspective, topological photonics can be combined with optical nonlinearities, leading toward new collective phenomena and novel strongly correlated states of light, such as an analog of the fractional quantum Hall effect.

Topological Photonics

The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

We have studied CdTe/CdMgTe microcavity samples containing 4 quantum wells and characterized by a vacuum field Rabi-splitting of 13.2 meV. Electron-hole pairs were excited at 7.3K by linearly-polarized light at 1.74 eV provided by a Ti:sapphire laser operating in the pulsed mode (at 80 MHz rate). Spectroscopic imaging in reciprocal space as well as near-field spectroscopy show that, above a critical stimulation threshold, polaritons in our microcavity undergo a spontaneous transition to a condensed phase characterized by the massive occupation of the polariton ground state. The coherence of this quantum state is evidenced by the spectral and angular narrowing of its emission. We point out the conditions which should be fulfilled to achieve BEC of microcavity polaritons. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Spontaneous phase condensation of CdTe exciton-polaritons

Two-photon pumping of excited exciton states in semiconductor quantum wells is a tool for realization of ultra-compact terahertz (THz) lasers based on stimulated optical transition between excited 2p and ground 1s exciton state. We show that the probability of two-photon absorption by a 2p-exciton is strongly dependent on the polarization of both photons. Variation of the threshold power for THz lasing by a factor of 5 is predicted by switching from linear to circular pumping. We calculate the polarization dependence of the THz emission and identify photon polarization configurations for achieving maximum THz photon generation quantum efficiency.

Polarization Control of Optically Pumped Terahertz Lasers

A novel semi-classical theory of exciton-polaritons in quantum wells (QWs) is presented. Time-resolved coherent optical spectra of QWs are described by the light coupling with ensembles of localized quantum dot-like exciton states. The ratio between reflection and resonant Rayleigh scattering (RRS) intensity gives a direct measure of the density of these excitonic dots. Good agreement with experimental data for time-resolved angle-dependent reflection and RRS from a GaAs single QW is achieved.

Theory of propagation and scattering of exciton-polaritons in quantum wells

http://link.springer.com/content/pdf/10.1007/978-3-642-59484-7_245.pdf

Resonant Rayleigh scattering of exciton-polaritons in multiple quantum well structures

Magnetic field induced edge currents propagate in opposite directions at opposite edges of a Hall bar. We consider a system that possesses just one edge: a M\"obius stripe. We show that if the carrier mean free path is less than the width of the stripe, magnetic field induced edge currents vanish. Instead, a stationary charge density wave is formed. Its profile is governed by the interplay between the magnetic field dependence of the chemical potential and the screened Coulomb repulsion of charge carriers. This effect offers an experimental tool for studies of the electron density of states in two-dimensional crystal films.

Alexey Kavokin

Papers

Spontaneous phase condensation of CdTe exciton-polaritons

Polarization Control of Optically Pumped Terahertz Lasers

Theory of propagation and scattering of exciton-polaritons in quantum wells

Resonant Rayleigh scattering of exciton-polaritons in multiple quantum well structures

Magnetic field induced formation of a stationary charge density wave in a conducting Möbius stripe